1) Technical Field
The present invention relates to an alarm apparatus for exchanging lamps of a wafer etching device and a method therefor, and more particularly, to an alarm apparatus for exchanging lamps of a wafer etching device, and a method for detecting disconnected lamps and the expected life span of a plurality of lamps that are provided in a semiconductor exposure apparatus to exchange the corresponding lamps, thereby minimizing process failures.
2) Description of Related Art
Fabricating semiconductor devices generally requires various process equipment such as diffusion equipment, deposition equipment, ion implantation equipment, etching equipment, and the likes. Dry etching equipment and dry stripping equipment, out of the etching equipment for accurately patterning wafers, are provided in their chambers with a plurality of lamps for allowing polymers to be attached to dome shaped covers of the chambers.
A lot of polymer particles float in an ascending current in the chamber while a stripping process is performed to remove a photo-resist layer on a wafer, or while an etching process is performed to pattern a wafer. At this time, the dome shaped cover serves to prevent these polymer particles from being deposited on a wafer.
FIG. 1 is a vertical cross sectional view of conventional dry etching equipment.
Referring to FIG. 1, a reaction chamber 1 is provided therein with an electrostatic chuck 2 on which a wafer W is loaded, supplied at its one side with a process gas, and the residual gas in the chamber 1 is pumped out just after processes complete. The reaction chamber 1 is covered at its topside with a transparent dome cover 3 and the topside is provided with a RF power coil 4, which serves to change the process gas to plasma type gas, and with a plurality lamps 5.
The etching equipment is generally provided therein with about eight lamps and the stripping equipment is provided therein with about 14 lamps.
The lamp 5 is designed to expose a wafer and accordingly emits heat at a temperature of about 80xc2x0 C. in the etching equipment and emits heat at a temperature of 275xc2x0 C. in the stripping equipment. It is very important for lamps of the etching equipment to maintain a proper temperature when heat is emitted therefrom, because particles created in the reaction chamber 1 are evenly diffused and adhere onto the dome cover 3 only when the chamber 1 continuously maintains a proper temperature above a predetermined temperature.
If a portion of the plurality of lamps fails in its function or is turned off, the adhesion distribution of the particles to the dome cover becomes uneven due to the variation in the surface temperature of the dome cover. As a result, there is a problem in that the particles in the reaction chamber 1 come off and are deposited on a wafer W, resulting in defective wafers.
In addition, there is a problem in the conventional alarm apparatus in that the state of the lamps (that is, whether the lamps are disconnected) cannot be checked without opening the upper cover of the alarm apparatus.
To solve the problems as described above, it is an object of the present invention to provide an alarm apparatus for checking an amount of electric current supplied to each of the lamps and timely exchanging only defective lamps if the amount of the current is less than a predetermined level, thereby minimizing process failures.
It is another object of the present invention to provide an alarm apparatus by which a worker can check whether lamps of a wafer etching equipment are electrically connected or disconnected without opening an upper cover of the equipment.
According to an aspect of the present invention, an apparatus comprises a plurality of lamps provided above a dome cover of a reaction chamber to uniformly maintain a constant temperature of the dome cover, current quantity detecting devices provided on each of electric lines supplying electric power to each of the lamps, a controller for checking the amount of electric current through each of the current quantity detecting devices to compare the detected amount of electric current with a predetermined amount of electric current, and an alarm indicating a proper time to exchange lamps having an amount of electric current less than a predetermined amount in response to a comparison result produced by the controller.
According to another aspect of the present invention, an apparatus comprises a plurality of lamps provided above a dome cover of a reaction chamber to uniformly maintain a constant temperature of the dome cover, coils winding around electric wires supplying electric power to each of the lamps so that electric current induced by each of the electric wires flows therein, electromagnetic resistance devices for converting the induced current values in the coils to resistance values to thereby detect the resistance values, a controller for checking the resistance values detected by the electromagnetic resistance devices to compare each with a predetermined resistance value, and an alarm indicating a time to replace lamps in response to a signal that is generated by the controller.